An exemplary embodiment of the present invention relates to an active damper and a driving method thereof. An AC input passed through a dimmer is transmitted to an active damper through a rectification circuit. The active damper includes a damper resistor connected to the rectification circuit, a damper switch connected to the damper resistor in parallel, and a delay circuit delaying a turn-on time of the damper switch by a predetermined initial period from a turn-on time of the dimmer.
Legal claims defining the scope of protection, as filed with the USPTO.
1. An active damper that receives an input current that is generated from an AC input that is passed through a dimmer and rectified by a rectification circuit, the active damper comprising: a damper resistor connected to the rectification circuit; a damper switch connected to the damper resistor in parallel; and a delay circuit delaying a turn-on time of the damper switch by a predetermined initial period from a turn-on time of the dimmer, wherein after the damper switch is turned-on, the damper switch is turned-off based on a voltage that is developed and sensed across the damper resistor.
2. The active damper of claim 1 , wherein the delay circuit comprises: a resistor including a first end connected to a first end of the damper resistor, and a capacitor connected between a second end of the resistor and a second end of the damper resistor.
3. The active damper of claim 2 , wherein the damper switch comprises a gate electrode connected to a node of the resistor and the capacitor.
4. The active damper of claim 1 , further comprising a reset circuit that resets the delay circuit based on the voltage that is developed and sensed across the damper resistor.
5. The active damper of claim 4 , wherein the reset circuit comprises a diode having a cathode connected to a first end of the damper resistor and an anode connected to a gate electrode of the damper switch.
6. The active damper of claim 1 , wherein the input current flows to a power supply through the active damper.
7. The active damper of claim 6 , wherein the input current flows through the damper resistor during an initial period, and then the input current flows through the damper switch after the initial period elapses.
8. A driving method of an active damper that receives an input current that is generated from an AC input that is passed through a dimmer and rectified by a rectification circuit, the active damper including a damper resistor and a damper switch connected to the damper resistor in parallel, the driving method comprising: charging a capacitor connected between a gate electrode and a source electrode of the damper switch during an initial period from a turn-on time of the dimmer; turning on the damper switch when a gate-source voltage of the damper switch reaches a threshold voltage by a voltage charged in the capacitor during the initial period; and after turning on the damper switch, turning off the damper switch based on a voltage that is developed and sensed across the damper resistor.
9. The driving method of claim 8 , further comprising, during a normal period during which the damper switch is turned on, constantly maintaining a both-end voltage of the damper resistor with the threshold voltage.
10. The driving method of claim 9 , further comprising; flowing the input current through the damper resistor during the initial period; and flowing the input current through the damper switch during a normal period.
11. The driving method of claim 8 , further comprising; connecting a diode when a both-end voltage of the damper resistor becomes lower than the threshold voltage of the damper switch by a decrease of the input current; and discharging the voltage charged in the capacitor through the connected diode.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
May 17, 2012
August 26, 2014
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